Red Bull is determined to tie Daniel Ricciardo and Max Verstappen down to contracts which run until the end of 2020.

While Red Bull knows it has Verstappen locked into his current deal until 2019, Ricciardo looks set to become a major player in next year's driver market as he will be in the final year of his existing deal. After spending all four of his seasons with Red Bull in machinery not capable of launching a championship bid he has made it clear the competitiveness of the team's 2018 contender will play a huge role in deciding his next move.

Ricciardo and Verstappen makes up arguably the best existing driver pairing on the grid and Horner does not want to lose either man any time soon.

Speaking about Ricciardo's contract, Horner said: "He is technically out of contract at the end of the 2018 season as he would have completed a five-year contract so what is absolutely clear is our intention to retain both of our drivers until 2020."

Red Bull has arguably the best driver pairing on the grid in Daniel Ricciardo and Max Verstappen. Mark Thompson/Getty Images

The future of Carlos Sainz has become clearer in recent weeks, with the Spaniard set to join Renault from Toro Rosso on a one-year loan deal next season. While the obvious benefit of that is the chance to drive for a factory outfit it also keeps Sainz as part of the Red Bull programme, meaning the team has a ready-made replacement for Ricciardo should he decide to drive elsewhere in 2019.

Helmut Marko, the man who oversees Red Bull's driver programme, was quoted during the Japanese Grand Prix as saying Ricciardo is on the open market after 2018 but Horner has downplayed that assessment.

"Carlos I wanted to keep under contract as an option should one of the drivers past year next not be with us. The absolute intention is we want Verstappen and Ricciardo in Red Bull Racing cars going forward. I think they both enjoy being in the team and the difference with Daniel is for the first time in his career at Red Bull he has got an insight into his contract. Helmut likes to state the obvious which is that he is on the open market but it doesn't mean that we don't want him."